# Activation error: Signature validation error

If you encounter this Signature Validation error, you must update to the latest version.

<figure><img src="https://3331713008-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MlCAurE6RSGoCmtmAET%2Fuploads%2FQUhLG2SEz29PeJi1gzrQ%2FpdfcSignatureError.png?alt=media&#x26;token=46b91ef3-78bd-447c-b1c5-9684db48956b" alt=""><figcaption></figcaption></figure>

**Download** and **install** the latest version of PDF Converter, which you can get here: <https://www.swingsoftware.com/download/dl-pdfc>

You can upgrade your existing installation or perform a fresh install.

Instructions for **upgrading** can be found here: <https://docs.swingsoftware.com/pdf-converter-for-notes/installation-uninstallation/upgrading>